Avionic door lock system

ABSTRACT

A security system adapted for use on an aircraft to prevent unauthorized access into a cockpit area of the aircraft via a cockpit door. The system includes a keypad accessible by individuals in a cabin area of the aircraft. A logic system is in communication with the keypad and also with a switch disposed inside the cockpit. Occupants of the cockpit, via the switch, have the ability to manually unlock the cockpit door, to deny the request for entry, or to do nothing, in which case the door will be automatically unlocked after the expiration of a predetermined time interval. No amount of tampering with the keypad or destruction of the keypad can unlock the cockpit door if the cockpit occupants decide to deny a request for entry via appropriate positioning of the switch. A pressure sensor in communication with the controller allows the door to be automatically unlocked in the event of a decompression condition occurring in the cockpit.

FIELD OF THE INVENTION

[0001] This invention relates to security systems, and more particularlyto a security system adapted for use on a mobile platform such as anaircraft for preventing unauthorized entry onto the cockpit of anaircraft.

BACKGROUND OF THE INVENTION

[0002] At the present time there is an increasing need for controllingaccess to particular areas of mobile platforms. More specifically, thereis an increasing need to control access to a cockpit of a commercialaircraft. Present day security systems often involve a simple lock orother system requiring the use of a key to unlock a door leading to acockpit. However, such systems can be inconvenient for flight attendantswho may need to periodically enter the cockpit area of an aircraft, suchsystems require a low force to open the door in case of decompressionevent.

[0003] Present day systems for preventing unauthorized access to thecockpit of a commercial aircraft through the use of a key can be forcedopen, and also can be foiled by an intruder if the intruder should gainaccess to the key. Accordingly, there is a strong need for a securitysystem for preventing unauthorized access into a cockpit of a commercialaircraft which does not suffer from the above-described limitations.

[0004] More specifically, there is a need for a security system for useon a commercial aircraft which provides the pilot, co-pilot or otheroccupants of the cockpit a signal that entry into the cockpit is beingrequested. Such a system would ideally give the individuals in thecockpit an opportunity to make an assessment as to whether or not entryinto the cockpit will be permitted either immediately, or whether entryshould be denied. There is further a need for such a system which allowsthe pilot, co-pilot or other cockpit occupant to unlock the doorseparating the cockpit from the cabin area of the aircraft from aconvenient location within the cockpit. Also required is the ability forthe flight attendant to unlock the door after alerting the pilot andco-pilot for a pre-set time, in case the pilot and co-pilot are bothincapacitated.

SUMMARY OF THE INVENTION

[0005] The above and other objects are provided by a security system inaccordance with a preferred embodiment of the present invention. Thesecurity system is particularly well adapted for use in mobile platformssuch as, but not limited to, commercial aircraft. The security systemoperates to lock a door which separates a cockpit from a passenger cabinarea and to allow occupants of the cockpit to receive signals indicatingthat a request for entry into the cockpit has been made by an individualin the passenger cabin area of the aircraft. The system further enablesan occupant of the cockpit to provide a signal to the system allowingimmediate unlocking of the cockpit door, or to deny the request tounlock the door.

[0006] The security system preferably includes a pressure sensor. Thepressure sensor causes the cockpit door to unlock when a difference inpressure between the cabin and cockpit is sensed.

[0007] The system generally includes a user input device which isaccessible by individuals in the cabin area. In one preferred form theinput device comprises a keypad. A controller incorporating a chime isdisposed in the cockpit. The logic system communicates with a controldevice positioned for convenient use by persons in the cockpit, as wellas with a lock operably associated with the cockpit door. In onepreferred form, the control device comprises a multi position rotaryswitch.

[0008] In a preferred embodiment the multi position rotary switchprovides three switch positions: an “AUTO” position, an “UNLOCK”position and a “DENY” position. An individual in the cabin area makes arequest to gain entry to the cockpit by entering a predetermined accesscode into the keypad. It will be appreciated that the access code is apre-programmed, restricted code that only individuals, such as flightattendants, would be apprised of in advance of entering the aircraft.When a correct access code is input to the keypad, the logic systemgenerates an aural and visual annunciation within the cockpit apprisingindividuals in the cockpit that a request to enter the cockpit has beenmade. If the switch is in the AUTO position, the occupants of thecockpit have a predetermined time period in which to decide either tounlock the cockpit door or to deny the request to enter. If a decisionis made to allow entry, the occupants may leave the switch in the AUTOposition, in which case the logic system will automatically unlock thelock associated with the cockpit door at the expiration of thepredetermined time interval. If the occupants decide that entry shouldnot be permitted, then the switch can be moved to the DENY position.This signals the logic system that the request to enter is being denied.The logic system will immediately disable the keypad and prevent furtherentry signals from being generated within the cockpit for apredetermined time thereafter. If the occupants decide to grantimmediate entry, then moving the switch to the UNLOCKED position sends asignal to the logic system that the lock to the cockpit door should beimmediately unlocked. The logic system then sends a signal to a suitabledevice, such as a solenoid, that immediately unlocks the cockpit door.The UNLOCK position unlocks the door at any time and stops all ongoingvisual and aural annunciations.

[0009] In one preferred embodiment the signal provided by the logicsystem is provided by a chime associated with a controller. The logicsystem also implements an intelligent series of time delays after arequest for entry has been made at the keypad. When such a request hasbeen made, the controller causes the chime to emit an audible signal tothe occupants of the cockpit. The controller also simultaneously beginsa first predetermined delay interval. If no action has been taken at thecontrol device by any occupant of the cockpit at the expiration of thefirst predetermined delay interval, a second audible warning is providedby the chime and a second predetermined delay interval is commenced. Atthe end of the second predetermined delay interval, if still no actionhas been taken by any occupant via the control device to either admit ordeny the request for entry, then the chime provides a continuous audiblewarning for a third predetermined time delay interval. At the end of thethird delay interval the controller automatically sends a signal to thesolenoid to unlock the lock to the cockpit door. A visual indicator alsopreferably flashes intermittently during the third delay intervalfurther signaling that the cockpit door will be unlocked within a veryshort time if no action is taken. This operating scheme thus provides ashort time period for the occupants of the cockpit to make an assessmentas to whether the request for entry to the cockpit should be granted ordenied. Conveniently, the door lock is automatically unlocked withoutintervention by the occupants of the cockpit provided the control deviceis in the AUTO position. The provision of both audible and visualsignals virtually eliminates the possibility that the occupants of thecockpit will not realize that a request for entry has been made. Itfurther allows automatic unlocking of the cockpit door unless anoccupant of the cockpit intervenes through appropriate control of theswitch.

[0010] It will be appreciated that the keypad described above does nothave the capability under any circumstances to unlock the door lock ofthe cockpit door. The lock is controlled strictly by signals receivedfrom the switch provided in the cockpit. Accordingly, no amount oftampering with the keypad, or even the destruction of the keypad, canresult in unlocking of the cockpit door once it is locked. Unlocking canbe accomplished only via the multi position switch.

[0011] Further areas of applicability of the present invention willbecome apparent from the detailed description provided hereinafter. Itshould be understood that the detailed description and specificexamples, while indicating the preferred embodiment of the invention,are intended for purposes of illustration only and are not intended tolimit the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

[0013]FIG. 1 is a simplified block diagram of a security system 10 inaccordance with a preferred embodiment of the present invention; and

[0014]FIG. 2 is a timeline of the three time delay intervals implementedby the controller of the system after a request to unlock the cockpitdoor is received.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The following description of the preferred embodiment(s) ismerely exemplary in nature and is in no way intended to limit theinvention, its application, or uses.

[0016] Referring to FIG. 1, there is shown a security system 10 forcontrolling access into a control center of a mobile platform. In thefollowing description, the mobile platform will be referred to as acommercial aircraft and the control center will be referred to as thecockpit of the aircraft. It will be appreciated, however, that thesystem 10 of the present invention is equally applicable to non-movingstructures where it is desired to closely control access to a sensitivearea of the structure. It is anticipated that the invention may alsofind applications on other mobile platforms such as ships or even buses.The system 10 advantageously includes only a limited number ofindependent component parts making it easily retrofitable to existingcommercial or other types of aircraft.

[0017] Referring further to FIG. 1, the system 10 generally includes auser input device in the form of a keypad 12 which is disposed in thepassenger cabin area 13 a of an aircraft 13, and in one preferredlocation on a door post assembly 15 a adjacent a door 15 of the aircraft13 facing the passenger cabin area. However, the keypad 12 may be placedin virtually any location where it can be conveniently accessed byflight crew members who may need to gain periodic access to the cockpit13 b of the aircraft 13.

[0018] The keypad 12 is in communication with a logic system 14. Thelogic system 14, in turn, is in communication with a control device 16,a circuit breaker 18 and a door lock solenoid 20. An ambient airpressure sensor 22 disposed in a cockpit 13 b of the aircraft 13communicates with the door lock solenoid 20 and the logic system 14. Thedoor lock solenoid 20 is operably associated with a door lock 26 for thecockpit door 15, as will be described in greater detail momentarily.

[0019] The logic system 14 comprises a suitable controller, and morepreferably an 8-bit controller. Advantageously, the controller 14includes a chime 24 which is used to generate an audible signal withinthe cockpit 13 b of the aircraft 13. The control device 16 is alsodisposed in the cockpit 13 b and may be mounted on an overhead panel, inan aisle stand panel or at any other conveniently accessible location inthe cockpit 13 b.

[0020] In a preferred embodiment the control device 16 comprises a multiposition rotary switch 28 having a first switch position 30 designatedas the “AUTO” position, a second switch position designated the “UNLOCK”position and a third switch position 34 designated as the “DENY”position. The switch 28 comprises a manually engageable switch element36 which is spring biased normally into the AUTO position. The switchelement 36 can be moved momentarily into either the UNLOCK position orthe DENY position. As soon as the switch element 36 is released,however, it is biased back to the AUTO position. An “UNLOCK” indicatorlight 38 is also disposed closely adjacent the switch 28, as is a “LOCKFAILED” indicator light 40. The UNLOCK indicator light 38 is illuminatedwhen a predetermined access code has been correctly entered into thekeypad 12, as will be described in greater detail momentarily. The LOCKFAILED indicator light 40 indicates that the solenoid 20 has notunlocked the lock 26 of the cockpit door 15.

[0021] The keypad 12 comprises a plurality of numeric keys 42 and anenter key 42 a, a first indicator light 44, a second indicator light 46and a third indicator light 48. The first indicator light 44 preferablycomprises a red LED for indicating that the door lock 26 is in a lockedcondition. Second indicator light 46 preferably comprises an amber LEDwhich is illuminated when a user inputs the predetermined access codecorrectly via the keys 42 and 42 a. Third indicator light 48 preferablycomprises a green LED which signals that the solenoid 20 has unlockedthe door lock 26.

[0022] The solenoid 20 includes a microswitch 50 for sensing theposition of a plunger 20 a of the solenoid 20. Accordingly, thecontroller 14 can verify that the plunger 20 a has been moved into thelocked position when the solenoid 20 is energized. This provides anadditional degree of security in the event the solenoid 20 fails and theplunger 20 a is not moved into the “LOCKED” position. In such instance,the LOCK FAILED indicator light 40 will be illuminated by the controller14 to provide an immediate visual indication of such a condition to theoccupants of the cockpit 13 b.

[0023] The ambient air pressure sensor 22 is used to detect a drop inpressure in the cockpit 13 b when the cockpit door 15 is closed. Such acondition might occur, for example, if the windshield of the aircraft 13was broken. In such a situation, it would be necessary to immediatelyunlock the cockpit door 15 to prevent complete decompression of thecockpit 13 b. The pressure sensor 22 is thus used to detect a drop inpressure within the cockpit 13 b and to immediately signal this event bydeenergizing the solenoid 20.

[0024] Referring to FIG. 2, a description will now be provided of thepredetermined time delay sequence that is implemented by the controller14. “TO” represents the instant that a user correctly enters thepredetermined access code via the keypad 12. This code preferablycomprises a three to eight digit numeric code. It is provided to flightattendants or other individuals, prior to entering the aircraft, who mayhave a need to periodically enter the cockpit 13 b while the aircraft 13is in operation. Immediately after receiving the correct access code,the controller 14 causes the chime 24 to generate an audible signalrepresented by pulses 52. Pulses 52 represent two “beeps” or other shortduration audible signals which immediately apprises the individuals inthe cockpit 13 b that a request for access to the cockpit has just beenmade. At T0, a first predetermined delay interval is commenced whichextends in to “T1”. At T1, if the controller 14 has not received eitherin UNLOCK or a DENY command via the switch 28 (i.e., the switch 28 hasnot been moved to either of these positions), then the controller causesthe chime 24 to again provide audible signals, represented by pulses 54,to remind the occupants of the cockpit 13 b that someone is requestingaccess to the cockpit. T1 represents the expiration of the first delayinterval and the beginning of a second delay interval.

[0025] At “T2”, if the switch 28 still has not been moved out of theAUTO position during the second delay interval, then the controller 14causes a third delay interval to be commenced. At T2 the controller 14causes the UNLOCKED indicator light 38 to be continuously illuminatedand the chime 24 is caused to output a continuous audible alert,represented by waveform 56, that the lock 26 of the door 15 will beunlocked within a very short time period if no operator action is takenvia the switch 28. At any time, an occupant in the cockpit 13 b may movethe switch element 36 of the switch 28 to the UNLOCK position 32, whichsignals the controller 14 to turn off the chime 24 and the UNLOCKEDindicator light 38, as well as to command solenoid 20 to unlock the lock26. Also at any time during the first delay interval, the second delayinterval or the third delay interval, an occupant in the cockpit 13 bmay move the switch element 36 to the DENY position 34. This signals thecontroller 14 to turn off the chime 24 and the UNLOCKED indicator light38, and further inhibits operation of the keypad 12 for a predeterminedtime thereafter. This predetermined time may vary but is preferably fora time interval of between five minutes to thirty minutes. During thistime, if an individual should again correctly enter the access code intothe keypad 12, no audible or visual signals would be provided by thechime 24 or UNLOCKED indicator light 38. After the expiration of thistime period, then the user may again input the access code into thekeypad 12 and make another request to access the cockpit 13 b.

[0026] At T3, as long as no operator selection has been made via theswitch 28 (i.e., meaning that the switch element 36 has remained in theAUTO position 30), the controller 14 causes the solenoid 20 to bedeenergized. This causes the door lock 26 to be unlocked. Thereafter,manual actuation of the door handle of the cockpit door 15 will allowthe door to be opened.

[0027] In the preferred embodiment described above, the delay intervalbetween T0 and T3 is user programmable from about 15 seconds to about120 seconds in 15 second increments. Preferably, the delay intervalbetween T2 and T3 has a minimum duration of at least 10 seconds. Theaudible signals represented by pulses 52 and 54 preferably comprise 0.5second duration audible signals having a frequency of preferably around500 Hz at approximately 75 dB. It will be appreciated, however, that theduration, frequency and intensity of these audible signals may bemodified to suit user preferences.

[0028] The UNLOCKED indicator light 38, when flashing during the thirddelay interval, preferably flashes at a 50% to 60% duty cycle, with 60%being the more preferred duty cycle. Again, however, the frequency atwhich this light flashes may be tailored to suit user preferences.

[0029] When the lock 26 of the cockpit door 15 is unlocked at point T3,the door is preferably maintained in the unlocked position for apredetermined time interval, and more preferably for at least about fiveseconds. Again, this delay interval could also be modified. During thistime period the solenoid 20 remains deenergzied. After this short timeinterval expires, the controller 14 again automatically energizes thesolenoid 20 to cause the lock 26 to lock the door 15.

[0030] The access code is preferably changeable from the controller 14.This is accomplished by engaging a “PROGRAM” key 58 on the controller 14as indicated in FIG. 1. Once this key is depressed, a new access codecan be entered at the keypad 12.

[0031] Another optional feature which may be implemented is a “doorbell” mode. This mode may be implemented by selecting a particular key,such as the “1” key on the keypad 12, followed by the “ENTER” key 42 a.This causes the chime 24 to generate an audible signal but does notbegin the time delay period represented between T0 and T3. In effect,the occupants of the cockpit 13 b are simply apprised that an individualin the cabin area 13 a of the aircraft 13 is requesting access to thecockpit. The audible signal may comprise one or more short durationsignals by the chime 24.

[0032] The system 10 of the present invention thus provides a means bywhich individuals in the cabin area of the aircraft can request accessto the cockpit, and can further initiate a process by which a lockedcockpit door will be automatically unlocked if no intervention is takenby occupants of the cockpit. The inclusion of the pressure sensor alsoensures that in the event of a decompression condition occurring in thecockpit, the cockpit door will be automatically and immediately unlockedso that the door can be quickly opened. Importantly, the system 10provides the occupants of the cockpit with the ultimate authority todeny the requested access if circumstances are such that the cockpitoccupants believe that the cockpit should remain secure from allindividuals in the cabin area.

[0033] Those skilled in the art can now appreciate from the foregoingdescription that the broad teachings of the present invention can beimplemented in a variety of forms. Therefore, while this invention hasbeen described in connection with particular examples thereof, the truescope of the invention should not be so limited since othermodifications will become apparent to the skilled practitioner upon astudy of the drawings, specification and following claims.

What is claimed is:
 1. A security system for preventing unauthorizedaccess to a control center of a mobile platform, wherein the controlcenter is separated from a passenger area of said mobile platform by adoor; said system comprising: a lock for locking said door; a user inputdevice accessible by individuals in said passenger area to input apredetermined access code to request unlocking of said door; acontroller responsive to said user input device for producing a signalwithin said control center when said access code is entered that entryto said control center has been requested by an individual within saidpassenger area; and a control device within said passenger area incommunication with said lock for allowing an individual in the controlcenter to unlock said door.
 2. The system of claim 1, wherein: saidcontrol device is in communication with said controller; wherein saidcontroller is in communication with said lock; and wherein said controldevice commands said controller to unlock said lock.
 3. The system ofclaim 1, wherein said control device comprises a switch for allowingsaid lock to be immediately unlocked.
 4. The system of claim 2, whereinsaid control device comprises a switch having a position signaling saidcontroller to unlock said lock after a predetermined time delay periodhas expired.
 5. The system of claim 2, wherein said control devicecomprises a switch for signaling said controller to ignore said requestfor entry and to maintain said lock in a locked position.
 6. A securitysystem for preventing unauthorized access to a cockpit of an aircraft,wherein the cockpit is separated from a cabin area by a cockpit door,the system comprising: a lock for locking the door in a closed position;a user input device for allowing an individual in said cabin area toinput a predetermined access code to request unlocking of the cockpitdoor; a controller responsive to said user input device for producing asignal when said access code is entered that entry to the cockpit hasbeen requested; and a switch in communication with said lock forallowing an individual in the cockpit to unlock said door.
 7. Thesecurity system of claim 6, wherein said lock is responsive to saidcontroller and said controller is responsive to said switch; and whereinsaid controller commands said lock to an unlocked position apredetermined delay time after said access code is entered at said userinput device.
 8. The security system of claim 6, wherein said controllercomprises a chime that produces an audible signal when said access codeis entered at said user input device.
 9. The security system of claim 6,wherein said switch comprises a multi-position switch in communicationwith said controller for enabling an individual on said cockpit to denyaccess to said cockpit and inhibit operation of said user input devicefor a predetermined time period after said access code had been enteredat said user input device.
 10. The security system of claim 6, whereinsaid switch is in communication with said controller and comprises amulti-position switch including: a first position in which said switchsignals said controller to unlock said lock when said predetermineddelay time has expired; a second position, in which said switch signalssaid controller to immediately unlock said lock; and a third position inwhich said switch signals said controller to maintain said lock in saidlocked position and to disable said user input device for saidpredetermined time period.
 11. The security system of claim 10, furthercomprising: a chime responsive to said controller for producing anaudible signal in said cockpit when said individual in said cabin areahas input said access code into said user input device.
 12. The securitysystem of claim 10, further comprising: an indicator light responsive tosaid controller for providing a visual indication to an individual onsaid cockpit that an individual in said cabin area has requested accessto said cockpit via said user input device.
 13. The system of claim 6,wherein said user input device comprises a keypad.
 14. The system ofclaim 13, wherein said keypad comprises: a first indicator lightindicating that said cockpit door is in said locked position; a secondindicator light indicating that said access code has been received bysaid controller; and a third indicator light indicating that said lockhas been moved to said unlocked position.
 15. A security system forpreventing unauthorized access to a cockpit of an aircraft, wherein thecockpit is separated from a cabin area by a cockpit door, the systemcomprising: a lock for locking the door in a closed position; a userkeypad for allowing an individual in said cabin area to input apredetermined access code to request unlocking of the cockpit door; acontroller responsive to said user input device for producing a signaldetectable in said cockpit when said access code is entered that entryto the cockpit has been requested; a switch in communication with saidcontroller for allowing an individual in the cockpit to select an actionincluding: commanding said controller to immediately unlock said lock;and commanding said controller to ignore a previous request by saidindividual, via said keypad, for access to said cockpit and to maintainsaid lock in a locked position.
 16. The system of claim 15, wherein saidswitch includes an automatic response position which signals saidcontroller to automatically unlock said lock after a predetermined timedelay period has expired after said access code has been input into saidkeypad.
 17. The system of claim 15, wherein said predetermined timedelay period includes at least: a first delay interval which commenceswhen said signal is generated that said access code has been entered insaid keypad; and a second delay interval during which said controllerproduces a second signal signaling to said occupants of said cockpitthat said controller will automatically unlock said lock at anexpiration of said first delay interval.
 18. The system of claim 15,wherein said predetermined time delay period includes: a first delayinterval which commences when said signal is generated that said accesscode has been entered in said keypad; a second delay interval whichcommences upon the expiration of said first delay interval, saidcontroller generating a second signal at a beginning of said seconddelay interval reminding occupants of said cockpit that cockpit door hasnot been unlocked or said request for entry denied via said switch; anda third delay interval during which said controller produces a thirdsignal signaling to said occupants of said cockpit that said controllerwill automatically unlock said lock at an expiration of said third delayinterval.
 19. The system of claim 15, wherein said keypad comprises: afirst indicator light for indicating that said lock is in a lockedcondition; and a second indicator light for indicating that said lockhas been moved into an unlocked condition.
 20. The system of claim 15,wherein said keypad comprises: a first indicator light for indicatingthat said lock is in a locked condition; a second indicator light forindicating that said lock has been moved into an unlocked condition; anda third indicator light for indicating that said access code has beenreceived by said controller and that said occupants in said cockpit havebeen apprised of said request for entry to said cockpit.
 21. The systemof claim 15, wherein said signal comprises an audible signal generatedby a chime, and wherein said chime is in communication with saidcontroller.
 22. The system of claim 15, wherein said controller operatesto inhibit further requests for entry to said cockpit for apredetermined delay interval if said switch is positioned to commandsaid controller to ignore said previous request for entry to saidcockpit.
 23. A method for securing a control center of a mobile platformfrom unauthorized entry, wherein the mobile platform includes a doorseparating said control center from a passenger area, the methodcomprising: using a lock to lock said door in a closed position; using auser input device to allow an individual in said passenger area to inputan access code to request entry to said control center; using acontroller to receive said request for entry and to provide a signal toan occupant in said control center that a request for entry to saidcontrol center has been made; using a control device for allowing saidoccupant to perform at least one action including: immediately unlockingsaid lock; and unlocking said lock only after the expiration of apredetermined time delay interval.